Re: [PATCH v14 07/12] remoteproc: mediatek: Remove dependency of MT8195 SCP L2TCM power control on dual-core SCP

From: Mathieu Poirier
Date: Tue Jul 11 2023 - 13:50:11 EST

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On Fri, Jul 07, 2023 at 01:26:07PM +0800, Tinghan Shen wrote:
> Previously, SCP core 0 controlled the power of L2TCM and dictated that
> SCP core 1 could only boot after SCP core 0. To address this constraint,
> extracted the power control flow of L2TCM and made it shared
> between both cores, enabling support of arbitrary boot order.

Definitely an improvement.

>
> The flow for controlling L2TCM power has been incorporated into the
> mt8195_scp_before_load() and mt8195_scp_stop() APIs, which are
> respectively invoked during the rproc->ops->start() and
> rproc->ops->stop() operations. These APIs effectively serve the same
> purpose as the rproc prepare()/unprepare() APIs."

I'm not fond of that custom API but it is so widespread in this driver that I
will go with it.

>
> Signed-off-by: Tinghan Shen <tinghan.shen@xxxxxxxxxxxx>
> ---
> drivers/remoteproc/mtk_common.h | 1 +
> drivers/remoteproc/mtk_scp.c | 80 ++++++++++++++++++++++++++-------
> 2 files changed, 66 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
> index 56395e8664cb..41e1b4732b75 100644
> --- a/drivers/remoteproc/mtk_common.h
> +++ b/drivers/remoteproc/mtk_common.h
> @@ -130,6 +130,7 @@ struct mtk_scp {
> struct rproc_subdev *rpmsg_subdev;
>
> struct list_head elem;
> + struct platform_device *cluster_pdev;

This isn't needed. rproc->dev.parent is pdev->dev. Use container_of() to
get to the platform device.

> };
>
> /**
> diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> index 3349488e5f21..94602272c05f 100644
> --- a/drivers/remoteproc/mtk_scp.c
> +++ b/drivers/remoteproc/mtk_scp.c
> @@ -29,6 +29,10 @@ struct mtk_scp_of_cluster {
> size_t l1tcm_size;
> phys_addr_t l1tcm_phys;
> struct list_head mtk_scp_list;
> +
> + /* Prevent concurrent operations of L2TCM power control. */
> + struct mutex l2tcm_lock;
> + u32 l2tcm_refcnt;
> };
>
> /**
> @@ -449,7 +453,7 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
>
> writel(1, scp->reg_base + MT8192_CORE0_SW_RSTN_SET);
>
> - /* enable SRAM clock */
> + /* enable SRAM power */
> scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> @@ -462,19 +466,38 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
> return 0;
> }
>
> -static int mt8195_scp_before_load(struct mtk_scp *scp)
> +static int mt8195_scp_l2tcm_on(struct mtk_scp *scp)
> {
> - /* clear SPM interrupt, SCP2SPM_IPC_CLR */
> - writel(0xff, scp->reg_base + MT8192_SCP2SPM_IPC_CLR);
> + struct mtk_scp_of_cluster *scp_cluster = platform_get_drvdata(scp->cluster_pdev);
> +
> + mutex_lock(&scp_cluster->l2tcm_lock);
> +
> + if (scp_cluster->l2tcm_refcnt == 0) {
> + /* clear SPM interrupt, SCP2SPM_IPC_CLR */
> + writel(0xff, scp->reg_base + MT8192_SCP2SPM_IPC_CLR);
> +
> + /* Power on L2TCM */
> + scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> + scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> + scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> + scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
> + MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
> + }
> +
> + scp_cluster->l2tcm_refcnt += 1;
>
> + mutex_unlock(&scp_cluster->l2tcm_lock);
> +
> + return 0;
> +}
> +
> +static int mt8195_scp_before_load(struct mtk_scp *scp)
> +{
> writel(1, scp->reg_base + MT8192_CORE0_SW_RSTN_SET);
>
> + mt8195_scp_l2tcm_on(scp);
> +
> /* enable SRAM clock */
> - scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> - scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> - scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> - scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
> - MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
> scp_sram_power_on(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
>
> /* enable MPU for all memory regions */
> @@ -487,6 +510,8 @@ static int mt8195_scp_c1_before_load(struct mtk_scp *scp)
> {
> scp->data->scp_reset_assert(scp);
>
> + mt8195_scp_l2tcm_on(scp);
> +
> scp_sram_power_on(scp->reg_base + MT8195_CPU1_SRAM_PD, 0);
>
> /* enable MPU for all memory regions */
> @@ -653,14 +678,30 @@ static void mt8192_scp_stop(struct mtk_scp *scp)
> writel(0, scp->reg_base + MT8192_CORE0_WDT_CFG);
> }
>
> +static void mt8195_scp_l2tcm_off(struct mtk_scp *scp)
> +{
> + struct mtk_scp_of_cluster *scp_cluster = platform_get_drvdata(scp->cluster_pdev);
> +
> + mutex_lock(&scp_cluster->l2tcm_lock);
> +

What happens if ->l2tcm_refcnt is 0 and this function is called?

> + scp_cluster->l2tcm_refcnt -= 1;
> +
> + if (scp_cluster->l2tcm_refcnt == 0) {
> + /* Power off L2TCM */
> + scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> + scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> + scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> + scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN, 0);
> + scp_sram_power_off(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
> + }
> +
> + mutex_unlock(&scp_cluster->l2tcm_lock);
> +}
> +
> static void mt8195_scp_stop(struct mtk_scp *scp)
> {
> - /* Disable SRAM clock */
> - scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> - scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> - scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> - scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
> - MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
> + mt8195_scp_l2tcm_off(scp);
> +
> scp_sram_power_off(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
>
> /* Disable SCP watchdog */
> @@ -669,6 +710,8 @@ static void mt8195_scp_stop(struct mtk_scp *scp)
>
> static void mt8195_scp_c1_stop(struct mtk_scp *scp)
> {
> + mt8195_scp_l2tcm_off(scp);
> +
> /* Power off CPU SRAM */
> scp_sram_power_off(scp->reg_base + MT8195_CPU1_SRAM_PD, 0);
>
> @@ -976,6 +1019,8 @@ static int scp_add_single_core(struct platform_device *pdev)
> if (IS_ERR(scp))
> return PTR_ERR(scp);
>
> + scp->cluster_pdev = pdev;
> +
> ret = rproc_add(scp->rproc);
> if (ret) {
> dev_err(dev, "Failed to add rproc\n");
> @@ -1028,6 +1073,8 @@ static int scp_add_multi_core(struct platform_device *pdev)
> goto init_fail;
> }
>
> + scp->cluster_pdev = pdev;
> +
> ret = rproc_add(scp->rproc);
> if (ret) {
> dev_err(dev, "Failed to add rproc of core %d\n", core_id);
> @@ -1114,6 +1161,7 @@ static int scp_probe(struct platform_device *pdev)
> }
>
> INIT_LIST_HEAD(&scp_cluster->mtk_scp_list);
> + mutex_init(&scp_cluster->l2tcm_lock);
> platform_set_drvdata(pdev, scp_cluster);
>
> ret = devm_of_platform_populate(dev);
> @@ -1137,6 +1185,8 @@ static void scp_remove(struct platform_device *pdev)
> rproc_del(scp->rproc);
> scp_free(scp);
> }
> +
> + mutex_destroy(&scp_cluster->l2tcm_lock);
> }
>
> static const struct mtk_scp_of_data mt8183_of_data = {
> --
> 2.18.0
>

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Previous message: Fenghua Yu: "Re: [PATCH v7 01/14] dmaengine: idxd: add wq driver name support for accel-config user tool"
Next in thread: Mathieu Poirier: "Re: [PATCH v14 07/12] remoteproc: mediatek: Remove dependency of MT8195 SCP L2TCM power control on dual-core SCP"
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